磁場作用下錫鉛合金方向性凝固之研究

Experimental Analysis of Making Pb-Sn Alloy by Using Directional Solidification Under Magnetic Fields

吳怡凡(Timothy Alfred Wu) ； 趙隆山(Long-Sun Chao) ； 張簡振甫(Chen-Fu ChangChjen)

《鑄造工程學刊》 42卷2期 (2016/06) Pp. 1-10

摘要

凝固為相當重要之材料製程技術，大多數之金屬材料必須先熔化成液體，再利用鑄造之方式做出成品或半成品。材料的微觀組織會在凝固過程，決定各項性質之優劣。因此如何由不同之工作條件，如溫度梯度、外加磁場等，來控制材料於凝固過程的微觀組織型態，強化材料的性質，故凝固學為重要的研究領域。方向性凝固是人為地控制融熔金屬的結晶生長方向，以獲得結晶方向相近的柱狀晶，甚至單晶結構的凝固方法。電磁凝固是以電場或磁場控制凝固過程，為較新的研究領域。本研究以錫－鉛合金(Sn-10wt%Pb)為研究材料，釹鐵硼強力磁鐵為外加磁場。主要之研究方法有巨觀金相組織、微觀金相組織觀察與截線法等。根據實驗結果，可得知利用高導熱係數的銅盒搭配低溫恆溫水槽，可製造高的溫度梯度，以達到方向性凝固目的，而在磁場作用下凝固確實會影響材料的微結構，線性磁場的施加方式可使方向性凝固之柱狀晶變細，排列較整齊，而環狀磁場的施加方式可以使方向性凝固之柱狀晶變粗。

關鍵字

方向性凝固 ； 電磁凝固 ； 錫-鉛合金 ； 共晶系統

並列摘要

Of all the processing techniques used in the manufacturing materials, solidification is probably the most important. Solidification affects the morphology control of microstructures. The microstructures of materials, which directly influence the mechanical and physical properties. The directional solidification process enables grain orientation to put in order along a specific direction, with this process, will decrease grain boundary (G.B.), which could improve mechanical properties of materials. The electromagnetic solidification process means the solidification process with the magnetic field or electric fields, the electromagnetic solidification is a new research field. In our study of sand mold casting and directional solidification, lead-tin (Sn-10wt%Pb) alloy is used as the casting material. Neodymium magnets are used to make magnetic fields. We used metallographic observation, including macrostructure, microstructure with optical microscope, and calculate grain size with linear intercept method, those are our materials analysis methods. According to the experimental results, casting process with a water-cooling copper chills, it can desired temperature gradient make the purpose of directional solidification. The microstructure of directional solidification process is affected by magnetic fields with experimental results. With linear magnetic field, has the thinner columnar structures than those of the one without magnetic field and with cyclic magnetic field, has the coarser columnar structures than those of the one without magnetic field.

並列關鍵字

directional solidification ； electromagnetic solidification ； lead-tin (Pb-Sn) alloy ； eutectic system